1. Field of the Invention
The present invention concerns a fixture for supporting a workpiece in a machine tool, in particular a crankshaft in an inclined-bed turning and milling machine, by means of two support elements arranged at a lateral distance from one another and radially moveable in relation to the workpiece, the support elements being held in a housing, having the workpiece lying on them and with their ends facing away from the workpiece being formed as two levers in a swiveling mounting in the housing, in which case the levers are driveably connected to one another by a threaded spindle, with the threaded spindle displaying counter-rotating thread sections in its areas corresponding to the two support elements, with each of the threaded sections engaging in a sliding block and held in a rotating mounting in the holes worked into the support elements at an angle perpendicular to the threaded spindle.
2. Description of the Prior Art
A support fixture of this type, also referred to as a steady rest, is familiar from EP 0 988 923 A1. Although the support elements are adjusted jointly by the threaded spindle, it is not possible to provide satisfactory support for a workpiece while it is being machined. This is because the forces arising are very considerable, in particular during roughing-down work, with the result that the support elements, which are only mutually supported by the threaded spindle, are deflected so that it is frequently necessary to accept production tolerances, particularly since the threaded sections which engage in one another have to allow for play. Consequently, the application range for this support fixture of prior art is limited.